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Unitas 29
Manual · 18.5‴ · Switzerland · 1920
Dimensions
41.6 mm
Height
6.50mm
Jewels
15
Power reserve
33h
Timegrapher
Beat rate
18,000bph
Frequency
2.5Hz
Reference: healthy amplitude ≈ 270–315° fully wound (>200° at 24 h); beat error ideally < 0.5 ms.
Movement
| Movement type |
Manual
Purely mechanical movements wound by hand via the crown, which tensions the mainspring to store energy. As the spring unwinds, it drives the gear train at a controlled rate set by the escapement and balance. Typical power reserves range from 38 to 80 hours, requiring daily or near-daily winding to keep the watch running.
|
|---|---|
| Winding type |
Stem Winding (Crown)
Winding the mainspring by turning the crown attached to the stem, transmitting torque through the winding pinion. Patented by Adrien Philippe in 1842, it replaced key winding and remains the standard manual winding method for both pocket watches and wristwatches.
|
| Setting type |
Stem Set (Crown Pull)
The dominant modern system: pulling the crown out to a setting position engages the hand-setting mechanism. Introduced in the late 19th century and refined into multi-position crowns (date, time, GMT). Used in virtually all modern wristwatches and most 20th-century pocket watches.
|
| Escapement type |
Swiss Lever
The undisputed standard of modern mechanical watchmaking. Through an elegant interplay between escape wheel, pallet fork, and balance, it delivers reliable impulses with the safety of 'draw' to keep the lever locked. Refined since the 18th century, it powers almost every quality mechanical wristwatch made today.
|
| Control type |
Balance Wheel
The heart of mechanical timepieces, the balance wheel is an oscillating component that, together with the hairspring, forms a harmonic oscillator regulating the gear train's pace. Its steady back-and-forth motion ensures the even release of energy from the mainspring, governing the watch's accuracy.
|
| Regulator type |
Pinned Regulator (or Index Regulator)
The most traditional regulator, consisting of a movable index pointer fitted with two curb pins (or a pin and a boot) that embrace the hairspring. Sliding the index along its scale changes the spring's active length, adjusting the rate. Simple, reliable, and easy to service, it remains the workhorse standard across countless mechanical movements.
|
Specifications
| Lignes | 18.5‴ |
|---|---|
| Shape |
Round
It is the most common form that we can find.
|
| Complications |
Sub Second
A small seconds hand typically located on a sub-dial and is separate from the central hour and minute hands. Originating from early pocket watches where the main balance wheel drove the seconds hand, it offers an elegant way to track the passage of time without crowding the main display. It remains a testimony to the watch's mechanical precision and history.
|
| Hand count | 3 |
| Hand sizes | 2.00 x 1.15 / 0.26mm |
| Further measures | Mounting Diameter (Dm): 41.0mm |
Origin & References
| Manufacturer | Unitas |
|---|---|
| Country | Switzerland |
| Launch year | 1920 |
| COSC certified | No |
| Signature | ca. 1920: A, 273 - 140846 (Alpina)
(Alpina 273, Unitas 31, H= 5.3mm) |
Notes
Remarks: open face calibre
option: Breguet hairspring
varying bridge shapes (cf. other calibres of the family)
attention: probably left handed ratchet-wheel screw
differences not known between 29, 359
likely just catalog designations for varying bridge shapes
Other data: balance staff: U992 stem: W1491 mainspring / battery: Zf3568, 2.10 x 16.0 x 0.20 x 460mm balance staff ronda: 2407 (18,5-21) balance staff ronda: 3685 (18,5-21) balance staff ronda: 3137 (18,5-21) stem ronda: 886 (18,5-21)
option: Breguet hairspring
varying bridge shapes (cf. other calibres of the family)
attention: probably left handed ratchet-wheel screw
differences not known between 29, 359
likely just catalog designations for varying bridge shapes
Other data: balance staff: U992 stem: W1491 mainspring / battery: Zf3568, 2.10 x 16.0 x 0.20 x 460mm balance staff ronda: 2407 (18,5-21) balance staff ronda: 3685 (18,5-21) balance staff ronda: 3137 (18,5-21) stem ronda: 886 (18,5-21)
Family
Series 29 - 6445
29: open face, H= 6.5mm
30: hunter, H= 6.5mm
31: open face, H= 5.3mm
32: hunter, H= 5.3mm
33: open face, H= 4.15mm
34: hunter, H= 4.15mm
245: open face, H= 4.7mm
same stem for H= 4.7...6.5mm:
361: open face, H= 4.7mm
362: hunter, H= 4.7mm
hands gear and barrel new:
231 : open face, H= 5.3mm
233 : open face, H= 4.15mm
234 : hunter, H= 4.15mm
426: sweep second, H= 7.9mm
new balance, wider mainspring:
429: open face, H= 6.5mm
430: hunter, H= 6.5mm
431: open face, H= 4.7mm
432: hunter, H= 4.7mm
new balance, mobile stud carrier, setting-lever spring like 6497:
6431: open face, H= 4.7mm
6437, 6445: open face, H= 4.7mm, modified mainspring
30: hunter, H= 6.5mm
31: open face, H= 5.3mm
32: hunter, H= 5.3mm
33: open face, H= 4.15mm
34: hunter, H= 4.15mm
245: open face, H= 4.7mm
same stem for H= 4.7...6.5mm:
361: open face, H= 4.7mm
362: hunter, H= 4.7mm
hands gear and barrel new:
231 : open face, H= 5.3mm
233 : open face, H= 4.15mm
234 : hunter, H= 4.15mm
426: sweep second, H= 7.9mm
new balance, wider mainspring:
429: open face, H= 6.5mm
430: hunter, H= 6.5mm
431: open face, H= 4.7mm
432: hunter, H= 4.7mm
new balance, mobile stud carrier, setting-lever spring like 6497:
6431: open face, H= 4.7mm
6437, 6445: open face, H= 4.7mm, modified mainspring
Related calibers
Unitas 231
Unitas 233
Unitas 234
Unitas 235
Unitas 237
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Unitas 241
Unitas 243
Unitas 245
Unitas 247
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Unitas 253
Unitas 255
Unitas 257
Unitas 259
Unitas 261
Unitas 263
Unitas 265
Unitas 267
Unitas 269
Unitas 271
Unitas 273
Unitas 275
Unitas 277
Unitas 279
Unitas 281
Unitas 29
Unitas 30
Unitas 31
Unitas 32
Unitas 33
Unitas 34
Unitas 359
Unitas 361
Unitas 362
Unitas 380
Unitas 382
Unitas 383
Unitas 384
Unitas 386
Unitas 404
Unitas 410
Unitas 429
Unitas 430
Unitas 431
Unitas 432
Unitas 435
Unitas 439
Unitas 441
Unitas 443
Unitas 444
Unitas 445
Unitas 446
Unitas 447
Unitas 449
Unitas 451
Unitas 453
Unitas 455
Unitas 457
Unitas 459
Unitas 465
Unitas 471
Unitas 473
Unitas 475
Unitas 477
Unitas 479
Unitas 481
Unitas 508
Unitas 6431
Unitas 6437
Unitas 6445
Compatible Parts
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